kopia lustrzana https://github.com/xdsopl/qsstv
86 wiersze
2.1 KiB
C++
86 wiersze
2.1 KiB
C++
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/*
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* File psdmean.c
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*
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* Calculates mean powerspectrum of input data
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* using blocklength lblock and nblocks as number
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* of blocks to be processed.
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*
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* Author M.Bos - PA0MBO
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* Date Feb 21st 2009
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*
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* resulting power spectral density of real input data
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* vector input[] is stored in psd[]
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* lblock is the length of the block of data to be
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* processed and nblock is the number of data blocks
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* to be processed
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*
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*/
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/*************************************************************************
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*
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* PA0MBO
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*
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* COPYRIGHT (C) 2009 M.Bos
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*
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* This file is part of the distribution package RXAMADRM
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*
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* This package is free software and you can redistribute is
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* and/or modify it under the terms of the GNU General Public License
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*
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* More details can be found in the accompanying file COPYING
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*************************************************************************/
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#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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#include <sys/types.h>
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#include <malloc.h>
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void rfft(float *, int, int);
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void psdmean(float *input, float *psd, int lblock, int nblocks)
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{
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float *pinput;
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int i, j;
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float tmpinbuf[1024];
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/* check for space allocated */
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if (lblock > 1024)
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{
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printf("lblokc param too large in call psdmean\n");
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exit(EXIT_FAILURE);
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}
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/* clear array psd before accumulating new data */
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for (i = 0; i < lblock / 2; i++)
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{
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psd[i] = 0.0;
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}
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/* loop over all blocks taking care to keep track of ptr in input */
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pinput = input;
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for (j = 0; j < nblocks; j++)
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{
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/* Now fill tmpinbuf with converted data from input */
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for (i = 0; i < lblock; i++)
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{
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tmpinbuf[i] = pinput[i];
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}
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rfft(tmpinbuf, lblock / 2, 1);
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for (i = 1; i < lblock / 2; ++i)
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{
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psd[i] += sqrt(tmpinbuf[i * 2] * tmpinbuf[i * 2] + tmpinbuf[2 * i + 1] * tmpinbuf[2 * i + 1]);
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}
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pinput += lblock; /* update pointer in input data */
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}
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for (i = 1; i < lblock / 2; ++i)
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psd[i] = (float) (10.0 * log(psd[i] + 1.0e-8) / 2.3025 - 14.0);
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}
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